in reply to top and STDERR hell...

FWIW, I get good results with backticks. For example: 

% perl -MList::Util=max -lwe '
print max map length, `COLUMNS=1000 top -bcS -n 1 2>err.txt`'
208

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The output is 81 if I omit the "COLUMNS=1000" bit.

My system is Debian Linux, and 

% top --version
top (procps version 2.0.7)

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the lowliest monk

Replies are listed 'Best First'.
Re^2: top and STDERR hell...
by DouglasDD (Beadle) on Jun 08, 2005 at 02:07 UTC
    Damn, backticks didn't occur to me. (somehow I've gotten in the habit of always using open(H, "app |")). I'll try this out as soon as I get back in the office tomorrow - will let you know.

    Thanks!
    ./ddd

[reply]
[d/l]

      Actually, it's not a backtick thing; that was just the first thing I tried; when I run your code I also get the desired results. Specifically: 

      # lll.pl
sub longestLineLength {
  my $longestLen = undef;
  for my $l ( @_ ) {
    if ( length($l) > $longestLen ) {
      $longestLen = length($l);
    }
  }
  return $longestLen;
}

1;  # propitiatory offering for require
__END__

# test03.pl
use strict;
use warnings;

require "lll.pl";

open (TOP, "COLUMNS=1000 /usr/bin/top -bcS -n 1 2>err.txt|")
  || die "open pipe from top failed $!";
print longestLineLength( <TOP> ) . "\n";
__END__
% perl test03.pl
208

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      the lowliest monk

[reply]
[d/l]
        Hmm, double-checked these and still get the same failing results. I can't explain the disparity between similar-sounding linux (procps) systems.

        Thanks for the data point.
        ./ddd

[reply]
      Nope. Same behavior with backticks.
      Darn.
[reply]

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